Due to the long service life and severe wear of small excavators, its performance will get worse and worse, leading to a series of failures.
The disadvantage of a small excavator is that the mechanical equipment does not increase the engine speed when the engine is started, which makes the engine start difficult and does not ignite. Also called: no car. So how will the weaknesses of startups be affected?
The reason for the failure is as follows
1. Engine oil, when the temperature exceeds 10 degrees Celsius, I suggest replacing 10w-30 engine oil, because 30 engine oil will be thinner and not too thick, which can increase the cold start speed of the engine and allow the engine to ignite smoothly. Some people may be worried here: If the oil is thin, will it affect the life of the engine or damage the engine? The oil pressure has nothing to do with the oil viscosity. Many people mistakenly think that the oil is thicker, the oil pressure is good, the engine is good, the oil is low, and the oil pressure is low. It may damage the engine. In fact, this is a big misunderstanding. As long as it is real oil, there is no pressure from organic oil. This is related to the viscosity of the oil. Motor oil is like human blood. Therefore, it is recommended that you use seasonal engine oil in different seasons to protect and extend the service life of the engine.
2. Before winter comes, the starter must be maintained, and the cover plate, carbon brushes and some worn items must be replaced. The rotor is clean, because the weather is cold, the oil will be thicker when it cools down, and the startup workload of this machine is much larger than in the warm season. It may be normal to use, but not in winter. Take care of it and spend a small amount of money to ensure that the starter has power to help you get started!
3. Battery (ie battery), battery voltage is not enough. In the cold winter, the battery energy will not completely evaporate, so every winter, it is the time to sell batteries. Of course, if possible, the driver may wish to find a thick quilt to wrap the battery or make a simple insulation. Although it may not work, it can at least extend battery life. If it is not too troublesome, you can take the battery out and store it in a warm place.
4. The pressure relief of the main safety valve is very low. The main relief valve limits the pressure of the entire hydraulic system to 32.5 MPa. For high pressures higher than this value, the main relief valve will open to release the pressure to protect the system from damage. If the spool orifice of the main safety valve is blocked due to poor oil quality, the spool is always open, or the safety pressure of the main safety valve is set very low. In fact, the safety pressure is very low, that is, the system pressure is very low. low.
5. Unloading valve failure
When the driver starts the engine and puts the joystick in neutral, the hydraulic oil output by the main pump returns directly to the tank through the unloading valve, and the unloading pressure is 3 MPa. If the oil is too dirty, the unloading valve slide valve will not close. When the machine is running, the output oil of the main pump will pass through the unloading valve and the oil tank, so that the system cannot build high pressure. Similarly, if the unloading valve is used to block the O-ring and tank of pressure oil, the main pump hydraulic oil will flow directly back to the tank.
6. Low main pump pressure
The excavator uses a double swash plate axial variable displacement piston pump. The output oil pressure of the main pump is generally 30MPa. If the wear between the plunger and the main pump cylinder or between the end face of the cylinder and the valve plate exceeds the standard (the contact area between the plunger and the cylinder should be less than 0.02 mm, it is the contact area), then the cylindrical contact between the end faces The area should be the valve plate. Not less than 90%), which will result in low output pressure of the main pump, which is reflected in the mechanical working device, and the whole machine works weakly.
It can be seen from the above introduction that we should do a good job in the maintenance of small excavators, so that there will be no more problems.